A patent document 1 (Japanese Published Unexamined Patent Application No. 2004-232464) discloses a fuel injector having the following structure. A swirler for forming a swirl fuel flow and an orifice plate (nozzle member) are put on a ring-shaped prominence for a swirler placement provided in a bottom of a nozzle member (nozzle holder) so as to keep a clearance between a nozzle member-inner diameter and a swirler-outer diameter. The orifice plate is temporarily press-fitted into the nozzle member. In this status, a positioning guide pin, which has an approximately the same diameter as a swirler inner diameter, is inserted in a through hole of the swirler such that a pin end becomes in contact with a valve seat. Thereafter, the orifice plate is press-fitted so as to hold the swirler between the nozzle member and the orifice plate, and temporary positioning is performed between the valve seat formed on the orifice plate and the swirler inner diameter. At this time, even when a center shift occurs between the valve seat and the swirler inner diameter, the center shift is absorbed with the clearance between the nozzle inner diameter and the swirler outer diameter.
Finally, from the status of this temporary positioning, the orifice plate is further press-fitted, thereby the swirler is engaged in the ring-shaped prominence on the swirler placement surface provided in the nozzle member, and the nozzle and the swirler are coaxially assembled. At this time, as the swirler held between the nozzle member and the orifice plate is constrained in a diameter direction by engagement in the ring-shaped projection, the concentricity between the swirler inner diameter and the valve seat can be maintained even when the positioning guide pin is pulled out.
Further, even when variation in height occurs among the nozzle, the swirler and the orifice plate, as the swirler is engaged in the ring-shaped prominence provided in the nozzle member, the entire height of the joined nozzle, the swirler and the orifice plate can be adjusted to a predetermined measurement.
The fuel injection in patent document 1 has a stopper as a stroke end of the movable valve (movable element) in a middle portion of the movable valve in its axial direction. Further, when the swirler and the orifice plate (nozzle member) have been built in the nozzle member (nozzle holder), the nozzle member is built on a yoke via the stopper in a stroke direction of the movable valve. In this structure, generally, the stoke of the movable valve is adjusted with the thickness of the stopper.
Further, in patent document 1, the swirler is engaged in the ring-shaped prominence on the swirler placement surface provided in the nozzle, and the entire height of the joined nozzle, the swirler and the orifice plate is adjusted to a predetermined measurement, however, the engagement of the orifice plate provided with the valve seat in the nozzle holding the orifice plate is not disclosed.
Accordingly, in patent document 1, there is no description about adjustment of stroke amount of the movable valve (movable element) with the amount of engagement between the nozzle member (nozzle holder) and the orifice plate (nozzle). Further, in a case where the nozzle member (nozzle holder) and the orifice plate (nozzle member) are welded, even when the orifice plate is press-fitted into the nozzle member, a relative positional relation between the nozzle member and the orifice plate may be shifted. This is not taken into consideration.
The present invention has been made in consideration of the above situation, and provides a fuel injector in which a stroke of a movable element can be infallibly adjusted and a stroke adjustment for the fuel injector.